Install nix on arch

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1

Hi! I’m trying to get started with nix for the first time. I installed nix on an existing arch linux installation using sudo pacman -S nix. I’m then following these instructions:
https://wiki.archlinux.org/title/Nix#Installation
and have enabled the daemon, added my user to the nix-users group, added a channel and updated it.

But the example with nix-env does not work. Ie nix-env -iA '<nixpkgs>.hello' gives error: attribute '<nixpkgs>' in selection path '<nixpkgs>.hello' not found. I suspect this is because I have no NIX_PATH env variable.

For example if I do nix-instantiate --eval -E '<nixpkgs>' I get an error again, however (NIX_PATH=/home/axel/.nix-defexpr/channels/stable/nixpkgs nix-instantiate --eval -E '<nixpkgs>') does work.

I see mentions of sourcing nix.sh online but I have no such file. Indeed the arch package removes this file:

and the mentioned bug report states that only nix-daemon.sh should be sourced. But that does not have any NIX_PATH in it. Where is this supposed to come from?

Not sure this is related but my ~/.nix-profile is a symlink to a non-existent /home/axel/.local/state/nix/profiles/profile.

Thanks in advance for any help!

2

Hey, welcome to NixOS discourse!

Is there anything that would prevent you from trying the other installation methods? I think the Determinate Systems installer is easier to use and easier to uninstall, in case you don’t like the experience. (Which I hope will not be necessary of course) :slight_smile:

3

Thanks for your reply!

No not really, the “native” just look the simplest, ie “just install nix with pacman” haha. But maybe that’s a red herring :slight_smile:

4

If you don’t have NIX_PATH set there is no chance that something containing <nixpkgs> will work:

This is how that variables is set on NixOS:

❯ echo $NIX_PATH
nixpkgs=flake:nixpkgs:/nix/var/nix/profiles/per-user/root/channels

But even on arch it could work, or maybe you should replace root with your user? (just check the content of /nix/var/nix/profiles/per-user/ folder)

5

Drop the <nixpkgs> part here.

6

These commands get it working for me on Arch (on WSL2):

sudo pacman -S nix

sudo usermod -a -G nixbld myusername

sudo usermod -a -G nix-users myusername

sudo systemctl enable nix-daemon

sudo systemctl start nix-daemon

systemctl status nix-daemon

nix-channel --add https://nixos.org/channels/nixpkgs-unstable nixpkgs

nix-channel --update

source ~/.bashrc

nix-shell -p nix-info --run "nix-info -m"

nix-env -iA 'nixpkgs.hello'

even though $NIX_PATH is empty.

7

For me this command gives error: empty attribute name in selection path '.hello'.

8

Definitely avoid nix-env to manage individual packages, it’s a massive beginner trap. https://stop-using-nix-env.privatevoid.net/ and Expression for a buildEnv-based declarative user environment. · GitHub describe some alternatives.

You have to drop the . as well. But there’s some subtleties and it all depends on some envvars, best to just not use it at all.